6. Roman roads were not built capriciously; and the road from Spain would not have crossed the Rhone at Tarascon unless there was some substantial reason for crossing it just there rather than a little higher up or a little lower down. This reason must have existed at the time when Hannibal crossed the Rhone a few years before the road was made; and by reckoning Hannibal’s march according to the Roman milestones, Polybios rather implies that Hannibal came that way. In any case Hannibal cannot have deviated greatly from the Roman road, as that ran near the coast, and Polybios says (iii. 41. 7) that Hannibal kept the sea upon his right hand (_dexion echôn_) as he marched. 7. After mentioning (iii. 37. 8) that the Rhone entered the sea by several mouths, Polybios says (iii. 42. 1) that Hannibal crossed it where it was a single stream, about four days’ march from the sea. It ceases to be a single stream at Arles, and divides there into branches leading to the mouths; and Arles is eight English miles below Tarascon and five-and-twenty from the sea. Four days at ten miles a day--see paragraph 3--would give 40 Roman miles, or 37 English, for the distance from Tarascon to the sea. But as Hannibal was coming from the west, he would have to turn inland at the westernmost mouth of the Rhone, somewhere near Aigues Mortes, whence the distance would be fully forty miles. No doubt, there were many crossing-places on the Rhone, and any of them might be known as a Diabasis--see paragraph 2--as this is merely the Greek for crossing. But there were many crossing-places on the Rhine, yet there was only one Trajectum, and many on the Euphrates, but only one Zeugma; and Polybios always speaks of the Diabasis of the Rhone as if there were no other. 8. According to Polybios (iii. 41. 2, 4–9, 44. 3, 45. 1–6, 47. 1, 49. 1) Scipio was taking a Roman army from Italy to Spain by sea, but stopped at the easternmost mouth of the Rhone and disembarked the army there, on hearing that Hannibal had already reached the crossing of the Rhone. He sent out cavalry to scout, and Hannibal likewise sent out cavalry, having heard of the arrival of the Roman ships. These two forces met: Scipio’s drove Hannibal’s back and pushed on far enough to see his camp, and then returned with information. Scipio forthwith (_parautica_) re-embarked the baggage and then marched up along the river with his whole force, as he was eager (_speudôn_) to attack the enemy. But on reaching the crossing, he found that the enemy had left their camp three days before, having started the morning after the encounter of the cavalry.